Titanium oxide coatings are known to have many uses due to their resistance to physical and chemical attack. For example, TiO2 coatings are very resistant to abrasion and have thus been used as an overcoat in multi-layer thin film stacks. Likewise it is known that such TiO2 coatings can protect more delicate coatings from, for example, oxidation due to exposure to the elements.
Such attributes of TiO2 coatings as just described could be beneficially utilized in, for example, photovoltaic devices, if such TiO2 coatings could also be made moderately electrically conductive, so as to enhance the overall efficiency of conversion of solar energy to electrical energy in such photovoltaic devices. It would also be highly desirable if such coatings could be manufactured economically so as to be useful in the large scale production of, for example, solar panels.
Deposition of TiO2 films having a wide variety of different properties has been reported in the scientific literature, for example: Kurtz, S. R. and Gordon, R. G., “Chemical Vapor Deposition of Doped TiO2 Thin Films”, Thin Solid Films, Vol. 147, pgs. 167-176 (1987) and Ginley, D. S. and Knotek, M. L., “Hydrogen in TiO2 Photoanodes”, J. Electrochem Soc., Vol. 126, pgs. 2163-2166, (1979)
Deposition of TiO2 films having selectively enhanced properties also appears in the patent literature, for example:
U.S. Pat. No. 4,780,306 describes an electrically conductive material of titanium dioxide crystal including at least one electrically conductive portion and at least one less conductive portion, and a method of producing the electrically conductive material, which includes the steps of applying a catalyst to the surface of the crystal and heating the crystal at a temperature of 300° C. to 600° C. in a gas atmosphere containing an oxidizing gas and a reducing gas.
U.S. Pat. No. 5,958,543 describes a thin film, magnetic disk media having micro-texturing provided by hydrogen-treated, sputter-deposited titanium nodules.
U.S. Pat. No. 7,037,830 describes a physical vapor deposition sputtering process for enhancing the preferred crystalline orientation of a titanium layer by using hydrogen before or during the deposition process.